explicitly set the C version to C99, fix linux-clang which seems to h…

…ave gotten a bit more pedantic (#214)

* explicitly set the C version to C99, fix linux-clang which seems to have gotten a bit more pedantic

* silence declaration-after-statement now that C++17/C99 are guaranteed

* placate this stupid new warning

CMakeLists.txt

@@ -26,6 +26,7 @@ endif()
 
 ################ Common compile flags
 
+set(CMAKE_C_STANDARD 99)
 set(CMAKE_CXX_STANDARD 17)
 
 if (MSVC)

nanoprintf.h

@@ -183,6 +183,7 @@ NPF_VISIBILITY int npf_vpprintf(npf_putc pc, void *pc_ctx, char const *format,
   #if NANOPRINTF_CLANG
     #pragma GCC diagnostic ignored "-Wc++98-compat-pedantic"
     #pragma GCC diagnostic ignored "-Wcovered-switch-default"
+    #pragma GCC diagnostic ignored "-Wdeclaration-after-statement"
   #elif NANOPRINTF_GCC_PAST_4_6
     #pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
   #endif

tests/include_multiple.c

@@ -31,9 +31,9 @@
 #include <stdio.h>
 
 int main(int c, char const *v[]) {
+  char buf[64];
   (void)c;
   (void)v;
-  char buf[64];
   npf_snprintf(buf, sizeof(buf), "%s", "hello");
   printf("%s\n", buf);
 }